The objective of the research proposed within is to study subsyndromal depressive individuals who are at increased risk for developing major forms of depressive disorders. Three lines of research, each aimed at assessing different aspects of the risk population, are described separately but will be undertaken concurrently, where subjects are assessed on multiple measures. Because no economical procedure is currently available to identify subjects at risk for depressive disorders, the first line of research concerns the evaluation of a first-stage case identification inventory (the General Behavior Inventory, GBI). The GBI is a self-report inventory that assesses the core behavioral characteristics of subsyndromal disorders. To proceed with its evaluation, major validation and calibration studies of the GBI are presented. These studies involve the administration of the GBI to full syndromal depressives in remission, outpatient subsyndromal cases, and outpatient personality disorder controls (RDC diagnosed). Moreover, high and low GBI scorers from the "normal" population will be interviewed "blind" for "caseness" and family history, and rated on the GBI by the interviewer. The second line of research examines a hormonal variable that may serve as a peripheral index of central predisposition to full syndromal depressive disorder. Plasma free cortisol values are assessed repeatedly (catheterization procedure) in subsyndromal and normal subjects during a 3-hour protocol. The protocol evaluates the integrity of the central inhibitory modulation of ACTH-cortisol release during rest, math-distracting noise-time pressure stress, and recovery of cortisol values. The third line of research is aimed at exploring the defining characteristics of subsyndromal disorders and at developing an index of severity of behavioral dysfunction. The studies evaluate behavioral variation in subsyndromal and normal subjects by having all subjects rate their behavior and personal events daily for 28 consecutive days. Analyses focus on the nature of behavioral variation and its relation to stress-initiation and cortisol dysfunction. These three lines of research will provide the empirical foundation for a prospective study of subsyndromal individuals to be initiated in the near future.